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T Jarkrans

Publications and source records attributed to T Jarkrans.

11 recordsLinked to original sources
PubMed1997

Image analysis based grading of bladder carcinoma. Comparison of object, texture and graph based methods and their reproducibility.

The possibility that computerized image analysis could increase the reproducibility of grading of bladder carcinoma as compared to conventional subjective grading made by pathologists was investigated. Object, texture and graph based analysis were carried out from Feulgen stained histological tissue sections. The object based features were extracted from gray scale images, binary images obtained by thresholding the nuclei and several other images derived through image processing operations. The textural features were based on the spatial gray-tone co-occurrence probability matrices and the graph based features were extracted from the minimum spanning trees connecting all nuclei. The large numbers of extracted features were evaluated in relation to subjective grading and to factors related to prognosis using multivariate statistical methods and multilayer backpropagation neural networks. All the methods were originally developed and tested on material from one patient and then tested for reproducibility on entirely different patient material. The results indicate reasonably good reproducibility for the best sets of features. In addition, image analysis based grading showed almost identical correlation to mitotic density and expression of p53 protein as subjective grading. It should thus be possible to use this kind of image analysis as a prognostic tool for bladder carcinoma.

Humans↗
PubMed1995

Grading of transitional cell bladder carcinoma by image analysis of histological sections.

Image analysis of histological sections was used to achieve a more objective malignancy grading of transitional cell carcinoma of the bladder. Images from Feulgen-stained sections from a clinical material of 197 tumours were analyzed. Features at various levels of analysis, e.g. mainly related to individual objects, neighbouring objects and the entire image, were analyzed. The features used were based on relational rather than individual nuclear features. With this technique, typical tissue architecture and degree of order/disorder can be described. These characteristics were compared by means of multivariate statistical methods with the subjective grading of the pathologists at our institution. This comparison provided the best subset of features and the agreement between the subjective and computer-based classification was 73%. The size, orientation and variation of the grey scale of the nuclei were particularly powerful. On a continuous scale, from grade 1 to 2A and 2B to 3, the four grades formed two distinct classes, low and high grade. In this distribution, the intermediate grade 2A was identified as a displaced grade 1 and the other intermediate grade 2B as a displaced grade 3.

Carcinoma, Transitional Cell↗
PubMed1994

Grading of transitional cell bladder carcinoma by texture analysis of histological sections.

Conventional subjective visual grading of malignancy in bladder carcinoma suffers from poor standardization. In an attempt to improve this by image analysis we carried out a texture analysis of a total of 197 images from Feulgen-stained histological tissue sections. The textural features used were based on the spatial gray-tone co-occurrence probability matrices for step-lengths 3, 4 and 6 pixels. These features were compared to the subjective grading by multivariate statistical methods. Using a two-stage hierarchical classifier 84.3% agreement was obtained between the subjective and computer-based classification. This was verified through the jackknifed classification technique.

Carcinoma, Transitional Cell↗
PubMed1986

Image cytometry in malignancy grading of breast cancer. Results in a prospective study with seven years of follow-up.

A fully automated system for image cytometry is presented. In combination with a special tumor sampling procedure, the system proved able to record with high reproducibility a large number of tumor cell population descriptors of high prognostic significance in a prospective study of breast cancer. These included the degree of abnormality of DNA distribution (strongly correlated with the proliferative rate) and some descriptors of shape and texture (strongly correlated with the grading system for breast cancer suggested by the World Health Organization). While the extreme complexity of a true malignancy grading system for breast cancer is underlined, the results of this study indicate that its creation is a possibility, given sufficient effort by interdisciplinary teams using modern sophisticated analytical techniques.

Breast Neoplasms↗
PubMed1985

A program for logistic prediction modelling.

A computer program has been developed that can be used for analysing a binary outcome variable and a set of regressors of type interval with a logistic (i.e. nonlinear) model.

Biometry↗
PubMed1983

Histopathological systems of breast cancer classification: reproducibility and clinical significance.

The inter- and intraobserver reproducibilities of the histopathological systems of breast cancer classification suggested by the World Health Organisation (WHO), the Armed Forces Institute of Pathology (AFIP) and Ackerman have been analysed. The reproducibilities of the three classification systems were only "fair" to "moderate" and no correlation with the five-year recurrence rate was found. Our results indicate that these classification systems are without biological significance and are useless for prognosis in the individual patient. When the tumours were classified according to degree of differentiation (high, moderate, low) or graded according to WHO (which includes both differentiation and nuclear atypia), however, there was a significant correlation with the five-year recurrence rate. Yet even such "reduced" subdivisions are of no value in judging prognosis for the individual patient at the time of diagnosis; rather, they are useful only in the follow-up analysis of groups of patients.

Breast Neoplasms↗
PubMed1981

Correlation between cytometric features and mitotic frequency in human breast carcinoma.

An evaluation of cytometric features of 142 human breast cancers was performed. Twenty-two cytometric features describing density, structure and shape were correlated with mitotic frequency and labeling index of some of the tumors and with the observed recurrence rate of the tumors within 3 years after removal of the breast. A new cytometric measure was also created by combining the four features most strongly correlated with mitotic frequency of the tumors. It was found that the variance of the nuclear area was the feature that was most strongly correlated with mitotic frequency and recurrence rate. No new cytometric measure created by combining the four features most strongly correlated with mitotic frequency, correlated as well as variance of nuclear area even though the four features were optimized by multiple regression analysis for their correlation with mitotic frequency.

Breast Neoplasms↗
PubMed1981

A morphometric expression of differentiation in fine-needle biopsies of breast cancer.

An automated method of particle sizing in fine-needle biopsies of human breast carcinomas is described. The average size of clusters of cells aspirated from breast carcinomas was strongly correlated with cytologic differentiation of the tumors and also with the recurrence rate 3 years after mastectomy so that smaller cluster size was associated with poor differentiation and a poor prognostic outcome. It thus seems possible to express in quantitative terms the degree of differentiation of breast carcinomas.

Biopsy, Needle↗
PubMed1981

Multifocal breast carcinoma.

The present study comprises 173 breast cancers in women living in Sweden. Mastectomy was performed and the surgical specimens were thoroughly scrutinized histopathologically with special attention given to the mammary tissue outside the dominant mass. Fifty-two patients (30 percent) had multifocal growth in the same breast as the dominant breast cancer. The patients have been followed up for 3 years after operation and compared with age-matched controls. The multifocal growth was not correlated with age, size of the tumor or death of the patient within 3 years. A previous diagnosis of benign breast disease was significantly more common among the cancer patients than among the controls, although it was unrelated to multifocal growth. This study stresses the importance of considering the high incidence of multifocal growth of breast cancer when discussing treatment by operation less radical than mastectomy.

Breast Diseases↗